Sensors have been used in the manufacturing industry for the last few decades and are of many types. These include pressure, proximity, contact, measurement, displacement and velocity sensors, rotary encoders, code readers, etc. – all using a variety of inputs such as electromagnetic, photoelectric, optical, radio and other signals. However, modern smart factories give sensors a new role to play.
“The next generation sensors are smart, communication-ready, and can be deployed faster than their predecessors – and are available at a fraction of their prices,” said Aloke Palsikar, Senior VP & Global Head Manufacturing Vertical at Tech Mahindra. “They consume a lot less power for operations, and can be brought in and taken out with considerable ease, making the adoption more widespread. Some of the sensor applications being used today are around Image Capture or Recognition and RFID or Nano Tags for product identification. Contact sensors and Precision motion sensing for shop floor safety applications (such as for collaborative robots), with multiple chemical sensors for fire, leakage and safety applications are among many available options. Most importantly, with real time data available from many more sensors working together, it is possible to construct algorithms to predict and monitor real time scenarios and take corrective actions almost instantaneously.”
Smart factories equipped with location tracking sensors are able to determine the precise positions of work-in-progress, tools and other production-relevant items within the facility, according to Andy Ward, CTO of Ubisense. “By tracking these items, and watching for interactions between them, the factory can monitor both the current state of the production process, and can identify when aspects of the process must be changed.”
For example, in a car factory where multiple vehicle models are run on the same production line, it is necessary to change the torque setting of electric screwdrivers when they are used on a car, so that they match the particular vehicle being worked upon. By tracking the locations of the cars and the locations of the tools in the plant in real-time, the smart factory can see when a tool is being used on a particular car, and can immediately issue the correct torque instruction to the tool over a wireless network. Then, the operator just has to align the tool on the nut and activate the tool, in the knowledge that the correct torque setting will always be used.
“Of course, this is a mission-critical application and a tracking system which supports it must be both accurate and reliable,” Ward continued. “Unfortunately, the factory environment is extremely challenging for the radio and optical tracking systems typically used in other industries - electromagnetic signals are reflected and obstructed by the copious amounts of metal in factories. However, new radio technologies like ultrawideband (UWB) radio allow centimetre-level real-time positioning even within the harsh factory environment.”